Read more about the project and investment conditions
More about the project
The time has come!
The builders want the new PC strand –10WPS
What is the new PC strand 10WPS?
It increases the prestressing tension
It has TWICE higher bond strength with concrete
It is 10% lighter with the same aggregate strength
10WPS is ten wire steel strand to use in prestressed concrete elements
It has the highest bond to the concrete among all 3-wire and 7-wire PC strands because of unique geometry.
It was developed by Russian engineers and it is currently being produced in small trial batches.
In many specialists’ opinion, once put into industrial scale production, it will replace all existing pretensioning strands on the market.
PC strands are used in prestressed concrete structures and elements, most of them are reinforced by 7-wire strands.
One of the most important properties of these strands is bond to the concrete which limits the prestressing tension of strands in the concrete.
Concrete manufacturers take the default bond strength of PC strands for granted - but in comparison with rebar forces it is very low. That makes concrete manufacturers increase the strength of concrete significantly to prevent strands’ slip.
But the bond strength of 7-wire PC strand is not enough to use it’s load capacity even in these high-tensile and expensive types of concrete and limits tension value by 70-80% of possible tension. The larger the strand, the lower limit.
It’s based on the strand design, where 6 wires are wrapped around the central one, cross section is close to the circular shape, so its bond with concrete is achieved by adhesion of a wire to concrete
Many customers prefer to use the indented PC strands with layer wires which have a mild periodical profile increasing bond to the concrete. These strands allow to decrease frequency of strands’ slippage in the manufacturing process, but the difference in the further characteristics of concrete elements reinforced by plain and indented PC strands is insignificant.
Cross-section and face of 7-wire PC strand.
Armasteel Company has developed 10-wire PC strands, where 9 layer wires are laid around the king wire into the helical structure with the triangular cross section.
These strands are patented and produced in trial batches and are marked as 10WPS.
Bond to the concrete of 10WPS strand is greatly increased in comparison with bond of 7-wire strand, it is kept in concrete by reaction forces of inclined surfaces, besides the adhesion bond. This feature allows to use full strength of strand and to increase its prestressing tension, so they are leading to significant economic effect.
Cross-section and face of 10WPS
10-wire strand - reducing the amount of prestressing steel and cement
The PC strands’ demand is constantly growing. I has increased from 1 to 6 mil tons a year in in the past few years. It may reach 20mln tons a year prognostically. The current confirmed demand for 10WPS already surpasses estimated output several-fold.
The high demand is supported by implementation of extruders, slipformers and vibroformers at the precast concrete plants for manufacture of hollowcore slabs, girders and other prestressed elements of buildings and structures
Benefit for consumers using 10WPS:
Productivity increasing without any reconstruction:
- Time keeping decrease in production of prestressed elements
- Eliminating strand slippage defects
Confirmed cost advantage is more than 40% from each ton of 10WPS strand
- Decrease of cement consumption
- Decrease of steel consumption
- Use of cheap inert aggregates
The expert opinions:
the chief engineer of Tyumen precast concrete plant №1
“We were the first to test the 10WPS at the extruding line by means of HC slabs reinforced by 10WPS and 7-wire strands in ratio 50:50 and their load capacity tests. The advantage of 10WPS strands in comparison with 7-wire strands in bond strength was great. At the moment of 7-wire strands’ slip, the 10WPS strands had zero slip until the total destruction of slabs. The load capacity increase 15%. The 10WPS strands did not slip due to their design and respectively they fully used their strength…»
the chief technologist AO “Barrikada” (Saint-Petersburg):
«we have been testing prestressed hollowcore slabs together with specialists of NIIZhB. The slabs were produced by extruding. The test results of the HC slabs reinforced by 10WPS strands in bond to the concrete are much better in comparison with indicators of slabs reinforced by 7-wire strands. This gives some economic advantages for prestressed concrete production…”
the technical director of “Kulonstroy” precast concrete plant
«We have made several series of tests of new 10WPS strand in extruded hollowcore slabs. We decreased the number of PC strands and the cement consumption, used pebble instead of crushed stone. All the slabs were tested successfully for rigidity, crack resistance and load capacity...»